/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.
 
This file is part of Quake III Arena source code.
 
Quake III Arena source code is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the License,
or (at your option) any later version.
 
Quake III Arena source code is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
 
You should have received a copy of the GNU General Public License
along with Foobar; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/
//

// cg_localents.c -- every frame, generate renderer commands for locally
// processed entities, like smoke puffs, gibs, shells, etc.

#include "cg_local.h"

#define	MAX_LOCAL_ENTITIES	512
localEntity_t	cg_localEntities[MAX_LOCAL_ENTITIES];
localEntity_t	cg_activeLocalEntities;		// double linked list
localEntity_t	*cg_freeLocalEntities;		// single linked list

/*
===================
CG_InitLocalEntities
 
This is called at startup and for tournement restarts
===================
*/
void	CG_InitLocalEntities( void )
{
    int		i;

    memset( cg_localEntities, 0, sizeof( cg_localEntities ) );
    cg_activeLocalEntities.next = &cg_activeLocalEntities;
    cg_activeLocalEntities.prev = &cg_activeLocalEntities;
    cg_freeLocalEntities = cg_localEntities;
    for ( i = 0 ; i < MAX_LOCAL_ENTITIES - 1 ; i++ )
    {
        cg_localEntities[i].next = &cg_localEntities[i+1];
    }
}


/*
==================
CG_FreeLocalEntity
==================
*/
void CG_FreeLocalEntity( localEntity_t *le )
{
    if ( !le->prev )
    {
        Com_Error( ERR_DROP,  "CG_FreeLocalEntity: not active" );
    }

    // remove from the doubly linked active list
    le->prev->next = le->next;
    le->next->prev = le->prev;

    // the free list is only singly linked
    le->next = cg_freeLocalEntities;
    cg_freeLocalEntities = le;
}

/*
===================
CG_AllocLocalEntity
 
Will allways succeed, even if it requires freeing an old active entity
===================
*/
localEntity_t	*CG_AllocLocalEntity( void )
{
    localEntity_t	*le;

    if ( !cg_freeLocalEntities )
    {
        // no free entities, so free the one at the end of the chain
        // remove the oldest active entity
        CG_FreeLocalEntity( cg_activeLocalEntities.prev );
    }

    le = cg_freeLocalEntities;
    cg_freeLocalEntities = cg_freeLocalEntities->next;

    memset( le, 0, sizeof( *le ) );

    // link into the active list
    le->next = cg_activeLocalEntities.next;
    le->prev = &cg_activeLocalEntities;
    cg_activeLocalEntities.next->prev = le;
    cg_activeLocalEntities.next = le;
    return le;
}


/*
====================================================================================
 
FRAGMENT PROCESSING
 
A fragment localentity interacts with the environment in some way (hitting walls),
or generates more localentities along a trail.
 
====================================================================================
*/

/*
================
CG_BloodTrail
 
Leave expanding blood puffs behind gibs
================
*/
void CG_BloodTrail( localEntity_t *le )
{
    int		t;
    int		t2;
    int		step;
    vec3_t	newOrigin;
    localEntity_t	*blood;

    step = 150;
    t = step * ( (cg.time - cg.frametime + step ) / step );
    t2 = step * ( cg.time / step );

    for ( ; t <= t2; t += step )
    {
        BG_EvaluateTrajectory( &le->pos, t, newOrigin );

        blood = CG_SmokePuff( newOrigin, vec3_origin,
                              20,		// radius
                              1, 1, 1, 1,	// color
                              2000,		// trailTime
                              t,		// startTime
                              0,		// fadeInTime
                              0,		// flags
                              cgs.media.bloodTrailShader );
        // use the optimized version
        blood->leType = LE_FALL_SCALE_FADE;
        // drop a total of 40 units over its lifetime
        blood->pos.trDelta[2] = 40;
    }
}


/*
================
CG_FragmentBounceMark
================
*/
void CG_FragmentBounceMark( localEntity_t *le, trace_t *trace )
{
    int			radius;

    if ( le->leMarkType == LEMT_BLOOD )
    {

        radius = 16 + (rand()&31);
        CG_ImpactMark( cgs.media.bloodMarkShader, trace->endpos, trace->plane.normal, random()*360,
                       1,1,1,1, qtrue, radius, qfalse );
    }
    else if ( le->leMarkType == LEMT_BURN )
    {

        radius = 8 + (rand()&15);
        CG_ImpactMark( cgs.media.burnMarkShader, trace->endpos, trace->plane.normal, random()*360,
                       1,1,1,1, qtrue, radius, qfalse );
    }


    // don't allow a fragment to make multiple marks, or they
    // pile up while settling
    le->leMarkType = LEMT_NONE;
}

/*
================
CG_FragmentBounceSound
================
*/
void CG_FragmentBounceSound( localEntity_t *le, trace_t *trace )
{
    if ( le->leBounceSoundType == LEBS_BLOOD )
    {
        // half the gibs will make splat sounds
        if ( rand() & 1 )
        {
            int r = rand()&3;
            sfxHandle_t	s;

            if ( r == 0 )
            {
                s = cgs.media.gibBounce1Sound;
            }
            else if ( r == 1 )
            {
                s = cgs.media.gibBounce2Sound;
            }
            else
            {
                s = cgs.media.gibBounce3Sound;
            }
            S_StartSound( trace->endpos, ENTITYNUM_WORLD, CHAN_AUTO, s );
        }
    }
    else if ( le->leBounceSoundType == LEBS_BRASS )
    {}

    // don't allow a fragment to make multiple bounce sounds,
    // or it gets too noisy as they settle
    le->leBounceSoundType = LEBS_NONE;
}


/*
================
CG_ReflectVelocity
================
*/
void CG_ReflectVelocity( localEntity_t *le, trace_t *trace )
{
    vec3_t	velocity;
    float	dot;
    int		hitTime;

    // reflect the velocity on the trace plane
    hitTime = cg.time - cg.frametime + cg.frametime * trace->fraction;
    BG_EvaluateTrajectoryDelta( &le->pos, hitTime, velocity );
    dot = DotProduct( velocity, trace->plane.normal );
    VectorMA( velocity, -2*dot, trace->plane.normal, le->pos.trDelta );

    VectorScale( le->pos.trDelta, le->bounceFactor, le->pos.trDelta );

    VectorCopy( trace->endpos, le->pos.trBase );
    le->pos.trTime = cg.time;


    // check for stop, making sure that even on low FPS systems it doesn't bobble
    if ( trace->allsolid ||
            ( trace->plane.normal[2] > 0 &&
              ( le->pos.trDelta[2] < 40 || le->pos.trDelta[2] < -cg.frametime * le->pos.trDelta[2] ) ) )
    {
        le->pos.trType = TR_STATIONARY;
    }
    else
    {}
}

/*
================
CG_AddFragment
================
*/
void CG_AddFragment( localEntity_t *le )
{
    vec3_t	newOrigin;
    trace_t	trace;

    if ( le->pos.trType == TR_STATIONARY )
    {
        // sink into the ground if near the removal time
        int		t;
        float	oldZ;

        t = le->endTime - cg.time;
        if ( t < SINK_TIME )
        {
            // we must use an explicit lighting origin, otherwise the
            // lighting would be lost as soon as the origin went
            // into the ground
            VectorCopy( le->refEntity.origin, le->refEntity.lightingOrigin );
            le->refEntity.renderfx |= RF_LIGHTING_ORIGIN;
            oldZ = le->refEntity.origin[2];
            le->refEntity.origin[2] -= 16 * ( 1.0 - (float)t / SINK_TIME );
            RE_AddRefEntityToScene( &le->refEntity );
            le->refEntity.origin[2] = oldZ;
        }
        else
        {
            RE_AddRefEntityToScene( &le->refEntity );
        }

        return;
    }

    // calculate new position
    BG_EvaluateTrajectory( &le->pos, cg.time, newOrigin );

    // trace a line from previous position to new position
    CG_Trace( &trace, le->refEntity.origin, NULL, NULL, newOrigin, -1, CONTENTS_SOLID );
    if ( trace.fraction == 1.0 )
    {
        // still in free fall
        VectorCopy( newOrigin, le->refEntity.origin );

        if ( le->leFlags & LEF_TUMBLE )
        {
            vec3_t angles;

            BG_EvaluateTrajectory( &le->angles, cg.time, angles );
            AnglesToAxis( angles, le->refEntity.axis );
        }

        RE_AddRefEntityToScene( &le->refEntity );

        // add a blood trail
        if ( le->leBounceSoundType == LEBS_BLOOD )
        {
            CG_BloodTrail( le );
        }

        return;
    }

    // if it is in a nodrop zone, remove it
    // this keeps gibs from waiting at the bottom of pits of death
    // and floating levels
    if ( CM_PointContents( trace.endpos, 0 ) & CONTENTS_NODROP )
    {
        CG_FreeLocalEntity( le );
        return;
    }

    // leave a mark
    CG_FragmentBounceMark( le, &trace );

    // do a bouncy sound
    CG_FragmentBounceSound( le, &trace );

    // reflect the velocity on the trace plane
    CG_ReflectVelocity( le, &trace );

    RE_AddRefEntityToScene( &le->refEntity );
}

/*
=====================================================================
 
TRIVIAL LOCAL ENTITIES
 
These only do simple scaling or modulation before passing to the renderer
=====================================================================
*/

/*
====================
CG_AddFadeRGB
====================
*/
void CG_AddFadeRGB( localEntity_t *le )
{
    refEntity_t *re;
    float c;

    re = &le->refEntity;

    c = ( le->endTime - cg.time ) * le->lifeRate;
    c *= 0xff;

    re->shaderRGBA[0] = le->color[0] * c;
    re->shaderRGBA[1] = le->color[1] * c;
    re->shaderRGBA[2] = le->color[2] * c;
    re->shaderRGBA[3] = le->color[3] * c;

    RE_AddRefEntityToScene( re );
}

/*
==================
CG_AddMoveScaleFade
==================
*/
static void CG_AddMoveScaleFade( localEntity_t *le )
{
    refEntity_t	*re;
    float		c;
    vec3_t		delta;
    float		len;

    re = &le->refEntity;

    if ( le->fadeInTime > le->startTime && cg.time < le->fadeInTime )
    {
        // fade / grow time
        c = 1.0 - (float) ( le->fadeInTime - cg.time ) / ( le->fadeInTime - le->startTime );
    }
    else
    {
        // fade / grow time
        c = ( le->endTime - cg.time ) * le->lifeRate;
    }

    re->shaderRGBA[3] = 0xff * c * le->color[3];

    if ( !( le->leFlags & LEF_PUFF_DONT_SCALE ) )
    {
        re->radius = le->radius * ( 1.0 - c ) + 8;
    }

    BG_EvaluateTrajectory( &le->pos, cg.time, re->origin );

    // if the view would be "inside" the sprite, kill the sprite
    // so it doesn't add too much overdraw
    VectorSubtract( re->origin, cg.refdef.vieworg, delta );
    len = VectorLength( delta );
    if ( len < le->radius )
    {
        CG_FreeLocalEntity( le );
        return;
    }

    RE_AddRefEntityToScene( re );
}


/*
===================
CG_AddScaleFade
 
For rocket smokes that hang in place, fade out, and are
removed if the view passes through them.
There are often many of these, so it needs to be simple.
===================
*/
static void CG_AddScaleFade( localEntity_t *le )
{
    refEntity_t	*re;
    float		c;
    vec3_t		delta;
    float		len;

    re = &le->refEntity;

    // fade / grow time
    c = ( le->endTime - cg.time ) * le->lifeRate;

    re->shaderRGBA[3] = 0xff * c * le->color[3];
    re->radius = le->radius * ( 1.0 - c ) + 8;

    // if the view would be "inside" the sprite, kill the sprite
    // so it doesn't add too much overdraw
    VectorSubtract( re->origin, cg.refdef.vieworg, delta );
    len = VectorLength( delta );
    if ( len < le->radius )
    {
        CG_FreeLocalEntity( le );
        return;
    }

    RE_AddRefEntityToScene( re );
}


/*
=================
CG_AddFallScaleFade
 
This is just an optimized CG_AddMoveScaleFade
For blood mists that drift down, fade out, and are
removed if the view passes through them.
There are often 100+ of these, so it needs to be simple.
=================
*/
static void CG_AddFallScaleFade( localEntity_t *le )
{
    refEntity_t	*re;
    float		c;
    vec3_t		delta;
    float		len;

    re = &le->refEntity;

    // fade time
    c = ( le->endTime - cg.time ) * le->lifeRate;

    re->shaderRGBA[3] = 0xff * c * le->color[3];

    re->origin[2] = le->pos.trBase[2] - ( 1.0 - c ) * le->pos.trDelta[2];

    re->radius = le->radius * ( 1.0 - c ) + 16;

    // if the view would be "inside" the sprite, kill the sprite
    // so it doesn't add too much overdraw
    VectorSubtract( re->origin, cg.refdef.vieworg, delta );
    len = VectorLength( delta );
    if ( len < le->radius )
    {
        CG_FreeLocalEntity( le );
        return;
    }

    RE_AddRefEntityToScene( re );
}



/*
================
CG_AddExplosion
================
*/
static void CG_AddExplosion( localEntity_t *ex )
{
    refEntity_t	*ent;

    ent = &ex->refEntity;

    // add the entity
    RE_AddRefEntityToScene(ent);

    // add the dlight
    if ( ex->light )
    {
        float		light;

        light = (float)( cg.time - ex->startTime ) / ( ex->endTime - ex->startTime );
        if ( light < 0.5 )
        {
            light = 1.0;
        }
        else
        {
            light = 1.0 - ( light - 0.5 ) * 2;
        }
        light = ex->light * light;
        RE_AddLightToScene(ent->origin, light, ex->lightColor[0], ex->lightColor[1], ex->lightColor[2] );
    }
}

/*
================
CG_AddSpriteExplosion
================
*/
static void CG_AddSpriteExplosion( localEntity_t *le )
{
    refEntity_t	re;
    float c;

    re = le->refEntity;

    c = ( le->endTime - cg.time ) / ( float ) ( le->endTime - le->startTime );
    if ( c > 1 )
    {
        c = 1.0;	// can happen during connection problems
    }

    re.shaderRGBA[0] = 0xff;
    re.shaderRGBA[1] = 0xff;
    re.shaderRGBA[2] = 0xff;
    re.shaderRGBA[3] = 0xff * c * 0.33;

    re.reType = RT_SPRITE;
    re.radius = 42 * ( 1.0 - c ) + 30;

    RE_AddRefEntityToScene( &re );

    // add the dlight
    if ( le->light )
    {
        float		light;

        light = (float)( cg.time - le->startTime ) / ( le->endTime - le->startTime );
        if ( light < 0.5 )
        {
            light = 1.0;
        }
        else
        {
            light = 1.0 - ( light - 0.5 ) * 2;
        }
        light = le->light * light;
        RE_AddLightToScene(re.origin, light, le->lightColor[0], le->lightColor[1], le->lightColor[2] );
    }
}

/*
===================
CG_AddScorePlum
===================
*/
#define NUMBER_SIZE		8

void CG_AddScorePlum( localEntity_t *le )
{
    refEntity_t	*re;
    vec3_t		origin, delta, dir, vec, up = {0, 0, 1};
    float		c, len;
    int			i, score, digits[10], numdigits, negative;

    re = &le->refEntity;

    c = ( le->endTime - cg.time ) * le->lifeRate;

    score = le->radius;
    if (score < 0)
    {
        re->shaderRGBA[0] = 0xff;
        re->shaderRGBA[1] = 0x11;
        re->shaderRGBA[2] = 0x11;
    }
    else
    {
        re->shaderRGBA[0] = 0xff;
        re->shaderRGBA[1] = 0xff;
        re->shaderRGBA[2] = 0xff;
        if (score >= 50)
        {
            re->shaderRGBA[1] = 0;
        }
        else if (score >= 20)
        {
            re->shaderRGBA[0] = re->shaderRGBA[1] = 0;
        }
        else if (score >= 10)
        {
            re->shaderRGBA[2] = 0;
        }
        else if (score >= 2)
        {
            re->shaderRGBA[0] = re->shaderRGBA[2] = 0;
        }

    }
    if (c < 0.25)
        re->shaderRGBA[3] = 0xff * 4 * c;
    else
        re->shaderRGBA[3] = 0xff;

    re->radius = NUMBER_SIZE / 2;

    VectorCopy(le->pos.trBase, origin);
    origin[2] += 110 - c * 100;

    VectorSubtract(cg.refdef.vieworg, origin, dir);
    CrossProduct(dir, up, vec);
    VectorNormalize(vec);

    VectorMA(origin, -10 + 20 * sin(c * 2 * M_PI), vec, origin);

    // if the view would be "inside" the sprite, kill the sprite
    // so it doesn't add too much overdraw
    VectorSubtract( origin, cg.refdef.vieworg, delta );
    len = VectorLength( delta );
    if ( len < 20 )
    {
        CG_FreeLocalEntity( le );
        return;
    }

    negative = qfalse;
    if (score < 0)
    {
        negative = qtrue;
        score = -score;
    }

    for (numdigits = 0; !(numdigits && !score); numdigits++)
    {
        digits[numdigits] = score % 10;
        score = score / 10;
    }

    if (negative)
    {
        digits[numdigits] = 10;
        numdigits++;
    }

    for (i = 0; i < numdigits; i++)
    {
        VectorMA(origin, (float) (((float) numdigits / 2) - i) * NUMBER_SIZE, vec, re->origin);
        re->customShader = cgs.media.numberShaders[digits[numdigits-1-i]];
        RE_AddRefEntityToScene( re );
    }
}




//==============================================================================

/*
===================
CG_AddLocalEntities
 
===================
*/
void CG_AddLocalEntities( void )
{
    localEntity_t	*le, *next;

    // walk the list backwards, so any new local entities generated
    // (trails, marks, etc) will be present this frame
    le = cg_activeLocalEntities.prev;
    for ( ; le != &cg_activeLocalEntities ; le = next )
    {
        // grab next now, so if the local entity is freed we
        // still have it
        next = le->prev;

        if ( cg.time >= le->endTime )
        {
            CG_FreeLocalEntity( le );
            continue;
        }
        switch ( le->leType )
        {
        default:
            Com_Error( ERR_DROP,  "Bad leType: %i", le->leType );
            break;

        case LE_MARK:
            break;

        case LE_SPRITE_EXPLOSION:
            CG_AddSpriteExplosion( le );
            break;

        case LE_EXPLOSION:
            CG_AddExplosion( le );
            break;

        case LE_FRAGMENT:			// gibs and brass
            CG_AddFragment( le );
            break;

        case LE_MOVE_SCALE_FADE:		// water bubbles
            CG_AddMoveScaleFade( le );
            break;

        case LE_FADE_RGB:				// teleporters, railtrails
            CG_AddFadeRGB( le );
            break;

        case LE_FALL_SCALE_FADE: // gib blood trails
            CG_AddFallScaleFade( le );
            break;

        case LE_SCALE_FADE:		// rocket trails
            CG_AddScaleFade( le );
            break;

        case LE_SCOREPLUM:
            CG_AddScorePlum( le );
            break;
        }
    }
}




